The invention relates to a method for producing a plastic material composite component during which a cavity in a plastic material injection molding machine is repleted with molten plastic material by injecting same and the chip is embedded in the plastic material. An electrical contact is made between the chip and a surface of the composite component.
Although the invention will hereinafter be described in relation to the production of so-called smart cards, it is to be understood that the invention is not limited to this field of application.
The term smart card is used to describe a plastic card with one or two laminated sides which usually carry some instructions and/or advertising printed thereon and/or certain safety features, for example a hologram, a magnetic strip, a photograph of the card holder, or the like. A module is embedded in the smart card. The module consists of an integrated semiconductor electronic circuit (chip) and, usually, of a contact-and-carrier plate carrying the chip. In the case of some cards, the chip coacts with a plurality of surface segments to form electric contacts that are accessible from the outside. In the case of other cards, antennas are provided in the card for the non-contact exchange of information, for example of data. Smart cards of that kind are employed as telephone cards, authentication cards for mobile communication equipment, as credit cards for money transfers, as authorization cards for medical insurance systems or the like.
The user of such cards introduces the smart card into, or moves past a card reader which thereby enters into communication with the electronic chip in the smart card via corresponding contacts or antenna means.
In order to enable smart cards to be simultanously used as advertising means, the smart cards preferably are produced in such a way that one or two films, preferably so-called labels, are employed to form one or both flat sides of the finished smart card. In this connection, the term "label" is understood to describe a film with, preferably, one printed side. The label carries the advertising imprint, or the like.
For producing the smart card, the label is introduced into the cavity of a plastic injection mold. For this purpose, the cavity has a flat, parallelepiped shape, and the labels are placed on the flat surfaces of the cavity.
The invention, further, is related to the production of similar cards, as have become known under the denomination "data-cards" or "PCMCIA". These cards are laminated on one or both flat sides with a metal foil or film and have the shape of a conventional credit card, however, are somewhat thicker so that even more complex electronic componentes may be embedded therein. Such data cards are used for securing data and are also used as access authorization elements for highest security standards. PCMCIA cards are, inter alia, used in portable electronic data processing and communication equipment, for example in notebooks and may contain a modem, supplemental memory or a standardized interface, for example for coupling the communication equipment to certain telephone or other data communication networks.
Such PCMCIA cards conventionally have a groove on a narrow front side, the groove, in turn, being internally equipped with female contact segments which, when the PCMCIA card is inserted into a corresponding PCMCIA slot, come into contact with corresponding male contact elements provided in the slot.
For producing either credit cards, smart cards or PCMCIA cards, molten plastic material is injected into an appropriate cavity of a mold. The plastic material may be any appropriate material, for example polystyrol, propylene, ABS or polycarbonate, resulting in a perfect adhesion between the labels and the plastic material after the termination of the injection process.
European patent document 0 399 868 discloses a process for manufacturing a smart card of the kind of interest. For doing so, the chip is first mounted on a metal band and is wired concurrently. The chip together with the metal band is then embedded in a plastic material so that a module is produced having a certain thickness. The module is configured such that its thickness corresponds to the height of the cavity within the mold. When the mold is closed a certain pressure is thus exerted on the module, fixing same at a certain predetermined position within the cavity.
According to this prior art method a contact area is provided being subdivided into certain segments according to the requirements of a specific application. The chip is connected to the segmented contact area by soldering its connectors onto individual segments of the contact area via contact wires. Subsequently, the chip and the contact area are embedded in a resin within a mold for producing the module which is then subsequently inserted between the foils and into the cavity, as described before. In a subsequent step the cavity is then repleted with plastic material by injecting same. In some applications an array of contact areas is arranged on a flat metal band or on an electrically conductive foil or film having the shape of a band. The chips are then individually bonded, are then subsequently embedded to generate modules and are finally separated from each other by cutting. This contacting of chips on bands is also known in the art as "tape-bonding".
Conventionally it had been considered as necessary to produce a module, i.e. the chip with its contact surface, as a separate element in order to be able to protect the chip against any adverse effects occurring during the manufacture of a smart card and in order to ensure a safe bonding with the contact area.
However, it is certainly disadvantageous that the modules are manufactured separately because this involves additional and time consuming production steps.
The prior art, further, has the disadvantage that the positioning of the module within the mold cavity may be guaranteed only with difficulties. The forces required for fixing the module within the cavity at a predetermined location may only be generated after the mold has been closed so that the modules might change their position during the closing of the mold.
It is, therefore, an object underlying the invention to improve a method, a component and a mold of the kind mentioned at the outset, so that the afore-mentioned disadvantages are obviated. In particular, the various method steps that are required for the production of such components shall be reduced in number and shall be simplified in order to enable a reliable and economical production.
These and other objects of the invention are achieved by a method for producing a plastic material composite component having a semiconductor chip embedded in the plastic material, the method comprising the steps of
providing a plastic material injection mold having a cavity; PA1 providing the chip in the cavity; PA1 providing electrical connection elements in the cavity; PA1 injecting molten plastic material into the cavity, thereby embedding the chip in the plastic material and simultaneously arranging the chip and the connection elements such that an electric contact is fixed between the chip and a surface of the cavity when the chip is arranged in the cavity. PA1 a first mold portion; PA1 a second mold portion adjoining the first mold portion with the cavity therebetween when the mold is in a closed operational position; PA1 means for inserting the chip into the cavity when the mold is in an open operational position; PA1 means for mechanically making an electrical contact between the chip and a contact surface on the component when the chip is arranged in the cavity, the contact making means being provided in the first mold portion and extending through an opening in the cavity.
The objects are, further, achieved by a plastic material composite component comprising at least one label configuring a flat side of the component, and a chip embedded in a plastic material adjoining the label, the chip being mounted on a carrier element and the carrier element being attached to the label, a contact surface being provided on the component, the chip having contact bumps electrically connected to the contact surface by soldering or riveting.
Moreover, the above-mentioned objects are achieved by a mold for injection molding a plastic material composite component having a chip embedded therein by injecting a molten plastic material into a cavity of the mold after inserting the chip into the cavity, the mold comprising:
The object underlying the invention is thus entirely achieved.
The invention makes the separate production of modules superfluous in which the modules are produced by embedding the chips and a contact area in a resin. Nevertheless, a precise and reliable contact between the chip and the surface of the composite component is achieved during the injection of the molten plastic material into the mold cavity.
Therefore, the production of such components is highly simplified because several production steps may be deleted and, further, it is only necessary to precisely insert the chip into the cavity and hold same on that position during the injection process.
According to the invention, the contact is fixed during the injection process, i.e. it is finally arranged because the corresponding contact elements had been inserted loosely into the cavity before.
In any case it is possible to insert the chip into the plastic material during the injection of the latter or to insert it into the cavity prior to injection.
In the scope of the present invention the term "chip" is to be understood in a broad sense and may comprise individual electronic components or assemblies or arrays of such components. In the colloquial language the term "chip" is normally related to an electronic component where the semiconductor substrate, i.e. the wafer, is entirely encapsulated in a plastic material housing and its contacts are bonded to mechanical contacts or contact tongues by well-known techniques. Although the present invention envisages to use such commercially available elements, it is also considered to use the wafers by themselves, i.e. wafers that have not already been embedded in a plastic material housing.
According to the invention it is preferred to use a semiconductor component having contact bumps on its surface and to embed same into the plastic material without surrounding the semiconductor component with another plastic material before.
This results in a further reduction of manufacturing steps, i.e. the manufacture of a housing or a module and, hence, results in substantial savings of time and money. Further, even smaller dimensions become possible because no separate and space consuming housings for the chips or the modules are required.
According to an embodiment of the invention the contacting itself is made during the injection time.
This feature has the advantage that a further step, i.e. the separate manufacture of the contact becomes superfluous. Therefore, a further reduction in cycle step and a further reduction of costs is achieved.
According to another embodiment of the invention the chip is arranged on a foil, film or a label which, later on, constitutes a flat side of the composite component. The chip and the label are synchronously inserted into the mold cavity.
The positioning of the label together with the chip may be made conventionally by applying a vacuum, by applying electrostatic forces or the like. As the position of the foil may be easily ensured when inserted in the cavity, the position of the chip is also ensured because the chip is fixedly attached to the label.
Therefore, in contrast to the prior art it is not necessary to use two separate positioning steps, one for the label and one for the module and no further steps must be taken to guarantee that the module will remain on its particular position. Thus, the position of the chip on the foil and, hence, within the cavity may even be guaranteed during the closing of the tool.
According to an alternate embodiment of the invention, the chip is not attached to the label prior to the beginning of the injection cycle. Instead, the chip is mounted on a part of the mold, for example by applying an appropriate adhesive and gluing the the chip on the tool.
In a preferred embodiment of the invention the chip has bumps on its surface and is electrically connected to the contact area.
This feature has the advantage that the contact bumps may be geometrically located accordingly so that they may immediately be soldered or connected by pressure to a corresponding counter-surface, thus establishing an electrically conductive connection. The contact bumps may be inserted into corresponding openings in the label. In such a way an electrically conductive connection to the contact area may be established without the need of a complex bonding process as used in the prior art where fine wires are bonded to the contact bumps on the semiconductor substrate.
It goes without saying that the term "contact bumps" shall include any contact points on the surface of the chip and may substantially vary in their specific design, depending from the particular chip or varying between various chip manufacturers. However, contact bumps are conventionally configured so as to withstand certain mechanical stress so that they may be soldered with a soldering agent melting at low temperatures or may be bonded accordingly.
The contact area itself may be generated either before or during the injection process. The generation of the contact area after the injection process is particularly preferred because during the injection process the fixing of the contacting occurs, i.e. the electrically conductive connection between the contact bumps and the composite component outside surface. Therefore, after the injecting the contact area may be manufactured particularly simply and may be connected with the contact. Further, it is also possible to only mechanically prearrange the contact during the injection and to complete same after the injection.
In a particularly preferred embodiment of the invention the contact bumps are configured as rivets being riveted with the label during the injection process. The rivets may preferably be designed as hollow rivets which can be deformed and thus riveted with appropriate dies or swages, provided on the injection mold.
In another preferred embodiment of the invention the chip may be attached to the label by simply inserting its contact bumps into corresponding openings in the label.
The chip may, however, also be glued to the label or may be soldered thereto. Further, the chip may also be applied to the label under the action of a spring. This may be made particularly if the label is a metallic foil.
If metallic foils are used, the chip is simultaneously screened against electromagnetic fields.
The metallic foil may comprise contact segments, thus enabling to use the metallic foil itself for the generation of the contact area.
The particular design of the segmented contact area may be effected by laser cutting, edging or other conventional methods as printing, galvanic deposition, vapor deposition or the like.
According to a further embodiment of the invention the contact bumps are plastically deformed during the printing of the contact area.
In some embodiments of the invention the chip is mounted to a carrier element. The carrier element may provide a mechanical of thermal protection of the chip during the subsequent injection process.
In preferred embodiments of the invention the label is connected with a second, parallel label, connected together in a sandwich arrangement.
If the electrical connection between the chip and the contact area on the surface of the composite component is made by soldering, it is particularly preferred to effect the soldering under the action of the heat being dissipated anyway by the hot molten plastic material injected into the cavity. The soldering is, thus, effected by itself without the necessity of using separate soldering equipment.
If the contact shall be made by riveting, it is preferred to arrange an appropriate riveting tool or swage on one of the mold portions in order to enable riveting during the production of the components, for example during the production of smart cards or PCMCIA cards.
It goes without saying that the features, mentioned before and those that will be explained hereafter, cannot only be used in the particular given combination but also in other combinations or alone without departing from the scope of the present invention.